linux-stable.git/include/linux/sched, branch v7.0.10

cgroup/cpuset: Reserve DL bandwidth only for root-domain moves

2026-05-23T11:09:37+00:00

commit 5dd74441cbf42c22e874450eb6a6bbb19390a216 upstream.

cpuset_can_attach() currently adds the bandwidth of all migrating
SCHED_DEADLINE tasks to sum_migrate_dl_bw. If the source and destination
cpuset effective CPU masks do not overlap, the whole sum is then
reserved in the destination root domain.

set_cpus_allowed_dl(), however, subtracts bandwidth from the source
root domain only when the affinity change really moves the task between
root domains. A DL task can move between cpusets that are still in the
same root domain, so including that task in sum_migrate_dl_bw can reserve
destination bandwidth without a matching source-side subtraction.

Share the root-domain move test with set_cpus_allowed_dl(). Keep
nr_migrate_dl_tasks counting all migrating deadline tasks for cpuset DL
task accounting, but add to sum_migrate_dl_bw only for tasks that need a
root-domain bandwidth move. Keep using the destination cpuset effective
CPU mask and leave the broader can_attach()/attach() transaction model
unchanged.

Fixes: 2ef269ef1ac0 ("cgroup/cpuset: Free DL BW in case can_attach() fails")
Cc: stable@vger.kernel.org # v6.10+
Signed-off-by: Guopeng Zhang 
Reviewed-by: Waiman Long 
Acked-by: Juri Lelli 
Tested-by: Juri Lelli 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

sched/topology: Fix sched_domain_span()

2026-05-23T11:08:30+00:00

[ Upstream commit e379dce8af11d8d6040b4348316a499bfd174bfb ]

Commit 8e8e23dea43e ("sched/topology: Compute sd_weight considering
cpuset partitions") ends up relying on the fact that structure
initialization should not touch the flexible array.

However, the official GCC specification for "Arrays of Length Zero"
[*] says:

  Although the size of a zero-length array is zero, an array member of
  this kind may increase the size of the enclosing type as a result of
  tail padding.

Additionally, structure initialization will zero tail padding. With
the end result that since offsetof(*type, member) < sizeof(*type),
array initialization will clobber the flex array.

Luckily, the way flexible array sizes are calculated is:

  sizeof(*type) + count * sizeof(*type->member)

This means we have the complete size of the flex array *outside* of
sizeof(*type), so use that instead of relying on the broken flex array
definition.

[*] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html

Fixes: 8e8e23dea43e ("sched/topology: Compute sd_weight considering cpuset partitions")
Reported-by: Nathan Chancellor 
Debugged-by: K Prateek Nayak 
Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Jon Hunter 
Tested-by: Chen Yu 
Tested-by: K Prateek Nayak 
Tested-by: Nathan Chancellor 
Link: https://patch.msgid.link/20260323093627.GY3738010@noisy.programming.kicks-ass.net
Signed-off-by: Sasha Levin

signal: Fix the lock_task_sighand() annotation

2026-05-23T11:08:29+00:00

[ Upstream commit 39be7b21af24d1d2ed3b18caac57dd219fef226e ]

lock_task_sighand() may return NULL. Make this clear in its lock context
annotation.

Fixes: 04e49d926f43 ("sched: Enable context analysis for core.c and fair.c")
Signed-off-by: Bart Van Assche 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Marco Elver 
Link: https://patch.msgid.link/20260225183244.4035378-3-bvanassche@acm.org
Signed-off-by: Sasha Levin

Merge tag 'x86_paravirt_for_v7.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-02-11T03:01:45+00:00

Pull x86 paravirt updates from Borislav Petkov:

 - A nice cleanup to the paravirt code containing a unification of the
   paravirt clock interface, taming the include hell by splitting the
   pv_ops structure and removing of a bunch of obsolete code (Juergen
   Gross)

* tag 'x86_paravirt_for_v7.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  x86/paravirt: Use XOR r32,r32 to clear register in pv_vcpu_is_preempted()
  x86/paravirt: Remove trailing semicolons from alternative asm templates
  x86/pvlocks: Move paravirt spinlock functions into own header
  x86/paravirt: Specify pv_ops array in paravirt macros
  x86/paravirt: Allow pv-calls outside paravirt.h
  objtool: Allow multiple pv_ops arrays
  x86/xen: Drop xen_mmu_ops
  x86/xen: Drop xen_cpu_ops
  x86/xen: Drop xen_irq_ops
  x86/paravirt: Move pv_native_*() prototypes to paravirt.c
  x86/paravirt: Introduce new paravirt-base.h header
  x86/paravirt: Move paravirt_sched_clock() related code into tsc.c
  x86/paravirt: Use common code for paravirt_steal_clock()
  riscv/paravirt: Use common code for paravirt_steal_clock()
  loongarch/paravirt: Use common code for paravirt_steal_clock()
  arm64/paravirt: Use common code for paravirt_steal_clock()
  arm/paravirt: Use common code for paravirt_steal_clock()
  sched: Move clock related paravirt code to kernel/sched
  paravirt: Remove asm/paravirt_api_clock.h
  x86/paravirt: Move thunk macros to paravirt_types.h
  ...

Merge tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-02-10T20:28:44+00:00

Pull locking updates from Ingo Molnar:
 "Lock debugging:

   - Implement compiler-driven static analysis locking context checking,
     using the upcoming Clang 22 compiler's context analysis features
     (Marco Elver)

     We removed Sparse context analysis support, because prior to
     removal even a defconfig kernel produced 1,700+ context tracking
     Sparse warnings, the overwhelming majority of which are false
     positives. On an allmodconfig kernel the number of false positive
     context tracking Sparse warnings grows to over 5,200... On the plus
     side of the balance actual locking bugs found by Sparse context
     analysis is also rather ... sparse: I found only 3 such commits in
     the last 3 years. So the rate of false positives and the
     maintenance overhead is rather high and there appears to be no
     active policy in place to achieve a zero-warnings baseline to move
     the annotations & fixers to developers who introduce new code.

     Clang context analysis is more complete and more aggressive in
     trying to find bugs, at least in principle. Plus it has a different
     model to enabling it: it's enabled subsystem by subsystem, which
     results in zero warnings on all relevant kernel builds (as far as
     our testing managed to cover it). Which allowed us to enable it by
     default, similar to other compiler warnings, with the expectation
     that there are no warnings going forward. This enforces a
     zero-warnings baseline on clang-22+ builds (Which are still limited
     in distribution, admittedly)

     Hopefully the Clang approach can lead to a more maintainable
     zero-warnings status quo and policy, with more and more subsystems
     and drivers enabling the feature. Context tracking can be enabled
     for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default
     disabled), but this will generate a lot of false positives.

     ( Having said that, Sparse support could still be added back,
       if anyone is interested - the removal patch is still
       relatively straightforward to revert at this stage. )

  Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)

    - Add support for Atomic and replace most Rust native
      AtomicBool usages with Atomic

    - Clean up LockClassKey and improve its documentation

    - Add missing Send and Sync trait implementation for SetOnce

    - Make ARef Unpin as it is supposed to be

    - Add __rust_helper to a few Rust helpers as a preparation for
      helper LTO

    - Inline various lock related functions to avoid additional function
      calls

  WW mutexes:

    - Extend ww_mutex tests and other test-ww_mutex updates (John
      Stultz)

  Misc fixes and cleanups:

    - rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd
      Bergmann)

    - locking/local_lock: Include more missing headers (Peter Zijlstra)

    - seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)

    - rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir
      Duberstein)"

* tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits)
  locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK
  rcu: Mark lockdep_assert_rcu_helper() __always_inline
  compiler-context-analysis: Remove __assume_ctx_lock from initializers
  tomoyo: Use scoped init guard
  crypto: Use scoped init guard
  kcov: Use scoped init guard
  compiler-context-analysis: Introduce scoped init guards
  cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers
  seqlock: fix scoped_seqlock_read kernel-doc
  tools: Update context analysis macros in compiler_types.h
  rust: sync: Replace `kernel::c_str!` with C-Strings
  rust: sync: Inline various lock related methods
  rust: helpers: Move #define __rust_helper out of atomic.c
  rust: wait: Add __rust_helper to helpers
  rust: time: Add __rust_helper to helpers
  rust: task: Add __rust_helper to helpers
  rust: sync: Add __rust_helper to helpers
  rust: refcount: Add __rust_helper to helpers
  rust: rcu: Add __rust_helper to helpers
  rust: processor: Add __rust_helper to helpers
  ...

Merge tag 'kthread-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks

2026-02-10T03:57:30+00:00

Pull kthread updates from Frederic Weisbecker:
 "The kthread code provides an infrastructure which manages the
  preferred affinity of unbound kthreads (node or custom cpumask)
  against housekeeping (CPU isolation) constraints and CPU hotplug
  events.

  One crucial missing piece is the handling of cpuset: when an isolated
  partition is created, deleted, or its CPUs updated, all the unbound
  kthreads in the top cpuset become indifferently affine to _all_ the
  non-isolated CPUs, possibly breaking their preferred affinity along
  the way.

  Solve this with performing the kthreads affinity update from cpuset to
  the kthreads consolidated relevant code instead so that preferred
  affinities are honoured and applied against the updated cpuset
  isolated partitions.

  The dispatch of the new isolated cpumasks to timers, workqueues and
  kthreads is performed by housekeeping, as per the nice Tejun's
  suggestion.

  As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set
  from boot defined domain isolation (through isolcpus=) and cpuset
  isolated partitions. Housekeeping cpumasks are now modifiable with a
  specific RCU based synchronization. A big step toward making
  nohz_full= also mutable through cpuset in the future"

* tag 'kthread-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks: (33 commits)
  doc: Add housekeeping documentation
  kthread: Document kthread_affine_preferred()
  kthread: Comment on the purpose and placement of kthread_affine_node() call
  kthread: Honour kthreads preferred affinity after cpuset changes
  sched/arm64: Move fallback task cpumask to HK_TYPE_DOMAIN
  sched: Switch the fallback task allowed cpumask to HK_TYPE_DOMAIN
  kthread: Rely on HK_TYPE_DOMAIN for preferred affinity management
  kthread: Include kthreadd to the managed affinity list
  kthread: Include unbound kthreads in the managed affinity list
  kthread: Refine naming of affinity related fields
  PCI: Remove superfluous HK_TYPE_WQ check
  sched/isolation: Remove HK_TYPE_TICK test from cpu_is_isolated()
  cpuset: Remove cpuset_cpu_is_isolated()
  timers/migration: Remove superfluous cpuset isolation test
  cpuset: Propagate cpuset isolation update to timers through housekeeping
  cpuset: Propagate cpuset isolation update to workqueue through housekeeping
  PCI: Flush PCI probe workqueue on cpuset isolated partition change
  sched/isolation: Flush vmstat workqueues on cpuset isolated partition change
  sched/isolation: Flush memcg workqueues on cpuset isolated partition change
  cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset
  ...

sched/isolation: Remove HK_TYPE_TICK test from cpu_is_isolated()

2026-02-03T14:23:34+00:00

It doesn't make sense to use nohz_full without also isolating the
related CPUs from the domain topology, either through the use of
isolcpus= or cpuset isolated partitions.

And now HK_TYPE_DOMAIN includes all kinds of domain isolated CPUs.

This means that HK_TYPE_DOMAIN should always be a subset of
HK_TYPE_KERNEL_NOISE (of which HK_TYPE_TICK is only an alias).

Therefore if a CPU is not HK_TYPE_DOMAIN, it shouldn't be
HK_TYPE_KERNEL_NOISE either. Testing the former is then enough.

Simplify cpu_is_isolated() accordingly.

Signed-off-by: Frederic Weisbecker 
Acked-by: Waiman Long 
Cc: Ingo Molnar 
Cc: Marco Crivellari 
Cc: Michal Hocko 
Cc: Peter Zijlstra 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Vlastimil Babka 
Cc: Waiman Long

cpuset: Remove cpuset_cpu_is_isolated()

2026-02-03T14:23:34+00:00

The set of cpuset isolated CPUs is now included in HK_TYPE_DOMAIN
housekeeping cpumask. There is no usecase left interested in just
checking what is isolated by cpuset and not by the isolcpus= kernel
boot parameter.

Signed-off-by: Frederic Weisbecker 
Reviewed-by: Waiman Long 
Cc: "Michal Koutný" 
Cc: Johannes Weiner 
Cc: Marco Crivellari 
Cc: Michal Hocko 
Cc: Peter Zijlstra 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Vlastimil Babka 
Cc: Waiman Long 
Cc: cgroups@vger.kernel.org

cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset

2026-02-03T14:23:34+00:00

Until now, HK_TYPE_DOMAIN used to only include boot defined isolated
CPUs passed through isolcpus= boot option. Users interested in also
knowing the runtime defined isolated CPUs through cpuset must use
different APIs: cpuset_cpu_is_isolated(), cpu_is_isolated(), etc...

There are many drawbacks to that approach:

1) Most interested subsystems want to know about all isolated CPUs, not
  just those defined on boot time.

2) cpuset_cpu_is_isolated() / cpu_is_isolated() are not synchronized with
  concurrent cpuset changes.

3) Further cpuset modifications are not propagated to subsystems

Solve 1) and 2) and centralize all isolated CPUs within the
HK_TYPE_DOMAIN housekeeping cpumask.

Subsystems can rely on RCU to synchronize against concurrent changes.

The propagation mentioned in 3) will be handled in further patches.

[Chen Ridong: Fix cpu_hotplug_lock deadlock and use correct static
branch API]

Signed-off-by: Frederic Weisbecker 
Reviewed-by: Waiman Long 
Reviewed-by: Chen Ridong 
Signed-off-by: Chen Ridong 
Cc: "Michal Koutný" 
Cc: Ingo Molnar 
Cc: Johannes Weiner 
Cc: Marco Crivellari 
Cc: Michal Hocko 
Cc: Peter Zijlstra 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Vlastimil Babka 
Cc: Waiman Long 
Cc: cgroups@vger.kernel.org

sched/isolation: Save boot defined domain flags

2026-02-03T14:23:33+00:00

HK_TYPE_DOMAIN will soon integrate not only boot defined isolcpus= CPUs
but also cpuset isolated partitions.

Housekeeping still needs a way to record what was initially passed
to isolcpus= in order to keep these CPUs isolated after a cpuset
isolated partition is modified or destroyed while containing some of
them.

Create a new HK_TYPE_DOMAIN_BOOT to keep track of those.

Signed-off-by: Frederic Weisbecker 
Reviewed-by: Phil Auld 
Reviewed-by: Waiman Long 
Cc: Ingo Molnar 
Cc: Marco Crivellari 
Cc: Michal Hocko 
Cc: Peter Zijlstra 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Vlastimil Babka 
Cc: Waiman Long